[1] He received his instruction in architecture in the service of his 'kinsman,' Roger Morris, 'Carpenter and principal engineer to the Board of Ordnance,' who died on 31 January 1749.
[2] The earliest executed work ascribed to Morris is Inveraray Castle (Gothic), begun in 1745, and after considerable delay completed in 1761.
It seems probable that Roger Morris was concerned in the design, and that the building was erected after his death under the supervision of his pupil Robert.
With S. Wright, Morris erected for George II the central portion of the lodge in Richmond Park, the design of which is sometimes attributed to Thomas Herbert, 10th earl of Pembroke.
With the Earl of Burlington, Morris designed, about 1750, Kirby Hall, Yorkshire, in the interior of which John Carr of York was employed.